Passion fruit leaf tea making technology

Abstract

The invention discloses a passion fruit leaf tea making process which takes passion fruit leaves as raw materials and sequentially comprises the steps of picking and acceptance inspection, spreading and withering, fixation, rolling, drying, refining, packaging and the like. Wherein in the enzyme deactivation process, high-temperature quick pan frying at the temperature of 180-260 DEG C is adopted, and braising and throwing are combined for alternate operation, so that quick enzyme inactivation, green gas loss and leaf softening are realized; in the rolling stage, cold rolling forming is carried out according to the principle of light-heavy-light, and tea juice is promoted to overflow; the drying stage is performed twice by gross fire and full fire, and finally the water content of the tea leaves is smaller than or equal to 7%. The temperature, time and strength parameters in the processing are finely controlled, so that the fresh leaves are effectively prevented from being oxidized, the chlorophyll, amino acid and specific aroma components of the passion fruits are reserved to the greatest extent, and the obtained tea soup is clear green, mellow in taste, fragrant and fruity, stable in quality and suitable for large-scale production and storage.

Description

Technical Field

[0001] This invention relates to the field of passion fruit leaf processing technology, and in particular to a process for making passion fruit leaf tea. Background Technology

[0002] Tea, as a traditional health beverage, has a long history and comes in many varieties. Most teas on the market are processed from plants of the Theaceae family (such as the buds and leaves of the tea tree), such as green tea, black tea, and oolong tea, and their processing technology is quite mature. In recent years, with the popularization of the concept of health, consumers' demand for substitute teas with special flavors and health benefits has been increasing, which has promoted the development and application of non-traditional tea plant resources.

[0003] Passion fruit, a popular tropical fruit, is known for its rich aroma and nutrients. Processed products such as juice and preserves are already common. However, the development and utilization of passion fruit leaves has lagged behind. Studies have shown that passion fruit leaves contain abundant flavonoids, polyphenols, amino acids, and other active ingredients, possessing traditional medicinal value such as clearing heat and detoxifying, reducing inflammation and relieving pain, and promoting digestion. It is a medicinal and edible plant resource with great development potential.

[0004] Currently, the use of passion fruit leaves is mostly limited to simply drying them and then steeping them in water for drinking, or using them as a raw material for traditional Chinese medicine decoction. These traditional methods have obvious drawbacks: First, simple drying cannot effectively deactivate the oxidases in the leaves. During the slow drying process, severe enzymatic oxidation and browning occur, resulting in a dark color in the finished product, losing the characteristics of green leaves and clear tea. Second, the processing is rough and cannot effectively dissipate the unpleasant "grassy smell" and form a pleasant tea aroma. Its taste often has a distinct astringent taste, and its flavor quality is poor. Finally, traditional processing methods cause significant damage to the heat-sensitive nutrients (such as vitamins and some active ingredients) in the leaves, failing to preserve its natural value to the maximum extent.

[0005] Therefore, there is an urgent need in this field for a dedicated processing technology for the large-scale production of high-quality passion fruit leaf tea, tailored to the characteristics of passion fruit leaves. This technology needs to solve the technical problems caused by existing processing methods, such as browning, poor aroma, astringent taste, and significant nutrient loss, so as to produce a passion fruit leaf tea product with a clear green liquor, delicate aroma, mellow taste, and good preservation of natural nutrients. Summary of the Invention

[0006] The purpose of this invention is to address the shortcomings of the prior art as described in the background section by proposing a passion fruit leaf tea production process. This process successfully solves the technical bottlenecks in the preservation of color, aroma, taste, and nutrients of passion fruit leaves during processing. It also forms a mature, stable, and easily promoted standardized production process, demonstrating significant technological progress and broad market application prospects.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A process for making passion fruit leaf tea includes the following steps:

[0009] S1. Fresh leaf picking and acceptance: Pick passion fruit fresh leaves with moderate tenderness and uniform buds, and after sorting and washing, cut them into leaf strips with a width of 0.8-1.2 cm.

[0010] S2. Spreading and wilting: Spread the leaf strips obtained in step S2 in a cool and ventilated place. The thickness of the spread strips should be 2-5 cm. Spread for 4-8 hours until the water loss rate of the fresh leaves is 10-15%.

[0011] S3. Blanching: Blanch the withered leaves by hand in a wok at 180-260℃ for 2-6 minutes, using a combination of steaming and tossing, until the leaves turn dark green, the grassy smell disappears, a fresh fragrance appears, and the water loss rate reaches 30-40%.

[0012] S4. Kneading: After the blanched leaves have cooled to below 60℃, knead them. The kneading process follows the principle of "light-heavy-light" pressure and the principle of "slow-fast-slow" speed, with a total duration of 20-60 minutes. During this period, the leaves are broken up and sieved.

[0013] S5. Drying: The rolled leaves are dried in stages to ensure that the moisture content of the tea leaves is ≤7%.

[0014] S6. Refining and Packaging: After the dried tea leaves are cooled, sorted, and graded, they are sealed in moisture-proof and light-proof materials.

[0015] As a preferred embodiment of the present invention, in step S1, the harvesting criteria for the fresh leaves are: intact buds and leaves, fresh, free from pests, and free from discolored buds.

[0016] As a preferred embodiment of the present invention, in step S2, the environmental conditions for withering are: temperature 20-28℃ and relative humidity 60-75%.

[0017] As a preferred embodiment of the present invention, in step S3, the amount of leaves added during the blanching process is adapted to the pan temperature, and the leaf temperature rises to above 80°C within 1 minute after adding the leaves, so as to quickly deactivate the oxidase activity.

[0018] As a preferred embodiment of the present invention, in step S3, the "combination of steaming and tossing" specifically means: first steaming for 20-40 seconds to ensure the leaves are heated evenly, then tossing for 10-20 seconds to release moisture and grassy aroma, and so on in an alternating cycle.

[0019] As a preferred embodiment of the present invention, the specific process of kneading in step S4 is as follows: initially, light pressure and slow kneading for 5-15 minutes; in the middle stage, heavy pressure and fast kneading for 10-30 minutes; and in the later stage, light pressure and slow kneading again for 5-15 minutes, so as to initially form strips, promote cell breakage, and finally shape the strips.

[0020] As a preferred embodiment of the present invention, step S5, the staged drying specifically includes:

[0021] Preheating stage: temperature 90-110℃, duration 10-20 minutes, followed by cooling and rehydration for 30-60 minutes;

[0022] The final drying stage: the temperature is 70-90℃, and the duration is 20-40 minutes, until the product is completely dry.

[0023] As a preferred embodiment of the present invention, in step S6, the sealed packaging is vacuum packaging or nitrogen-filled packaging.

[0024] In a preferred embodiment of the present invention, in step S6, the grading is based on the tightness of the tea leaves, the uniformity of the color, the purity of the aroma, and the richness of the flavor.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] 1. Effectively maintains the superior quality of "clear soup and green leaves": Through the core fixation process of "high temperature and fast fixation", the activity of oxidase in fresh leaves can be quickly and thoroughly deactivated, effectively stopping the enzymatic oxidation reaction of polyphenols. This solves the problem of leaf browning caused by traditional sun-drying methods, allowing the finished tea to retain chlorophyll to the maximum extent. After brewing, the soup is clear and green and the leaves are fresh, forming the unique quality characteristics of passion fruit leaf tea.

[0027] 2. Significantly improves and fixes the aroma and flavor of tea: The "withering" process promotes the volatilization of grassy aromas, and combined with the "combined withering and tossing" fixation technique, while thoroughly releasing the low-boiling-point grassy aromas, it also develops a delicate leaf and fruity fragrance. Subsequent "cold rolling" and staged "drying" processes further remove the astringent taste, promote the formation and fixation of aromas, and ultimately result in a tea with a pure, delicate, and lasting aroma, a mellow taste, and a refreshing aftertaste, completely eliminating the astringent off-flavors caused by simple processing.

[0028] 3. Maximize the preservation of natural nutrients: This process emphasizes rapid dehydration and precise temperature and time control. The entire processing flow is interconnected, avoiding the destruction of heat-sensitive substances (such as vitamins, amino acids, flavonoids, etc.) caused by prolonged high temperatures or fermentation. This allows the finished tea to retain more of the natural active ingredients in passion fruit leaves and better exert its potential health benefits.

[0029] 4. Strong process controllability and stable product quality: This invention precisely defines the parameters of each key process (such as withering water loss rate, fixation temperature and time, rolling force and duration, drying temperature and final moisture content), forming a standardized and replicable processing technology solution. This effectively reduces quality fluctuations caused by differences in individual experience, laying the foundation for the large-scale and stable production of high-quality passion fruit leaf tea.

[0030] 5. Expanding the comprehensive utilization value of passion fruit resources: This invention provides the passion fruit planting industry with a new value-added avenue besides fresh fruit sales, namely, the high-value-added development of its leaves. This not only improves the economic benefits of the industry but also aligns with the concept of green and sustainable agricultural development. Detailed Implementation

[0031] The invention will be more readily understood by referring to the following detailed description of preferred embodiments and included examples. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. In case of conflict, the definitions in this specification shall prevail.

[0032] As used herein, the terms “prepared from” and “comprising” are synonymous. The terms “comprising,” “including,” “having,” “containing,” or any other variations thereof, as used herein, are intended to cover non-exclusive inclusion. For example, a composition, step, method, article, or apparatus that includes the listed elements is not necessarily limited to those elements, but may include other elements not expressly listed or elements inherent to such composition, step, method, article, or apparatus.

[0033] The conjunction "composed of..." excludes any unspecified elements, steps, or components. If used in a claim, this phrase makes the claim closed, excluding materials other than those described, except for associated conventional impurities. When the phrase "composed of..." appears in a clause of the body of a claim rather than immediately following it, it limits only the elements described in that clause; other elements are not excluded from the claim as a whole.

[0034] When a quantity, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pair of any upper or preferred value with any lower or preferred value, regardless of whether the range is disclosed individually. For example, when the range “1 to 5” is disclosed, the described range should be interpreted as including the ranges “1 to 4”, “1 to 3”, “1 to 2”, “1 to 2 and 4 to 5”, “1 to 3 and 5”, etc. When numerical ranges are described herein, unless otherwise stated, the range is intended to include its endpoints and all integers and fractions within that range.

[0035] The singular form includes the plural objects of discussion unless the context clearly indicates otherwise. "Optional" or "any one" means that the matter or event described thereafter may or may not occur, and the description includes both the possibility that the event occurs and the possibility that the event does not occur.

[0036] Approximate terms used in the specification and claims to modify quantities indicate that the invention is not limited to that specific quantity, but also includes acceptable modifications close to that quantity that do not alter the relevant essential function. Correspondingly, the use of "about," "approximately," etc., to modify a numerical value means that the invention is not limited to that precise value. In some instances, approximate terms may correspond to the precision of the instrument used to measure the value. In this application's specification and claims, scope definitions can be combined and / or interchanged, unless otherwise stated, these scopes include all subscopes contained therein.

[0037] Furthermore, the indefinite articles “a” and “an” preceding the elements or components of this invention do not impose any limitation on the quantity requirement (i.e., the number of times) of the elements or components. Therefore, “an” or “a” should be interpreted as including one or at least one, and the singular form of an element or component also includes the plural form, unless the quantity clearly refers to the singular form.

[0038] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0039] Passion fruit has both medicinal and edible uses; its leaves also possess certain medicinal value, with the following common effects:

[0040] Clearing heat and detoxifying: Traditionally used to relieve symptoms such as sore throat and cough caused by wind-heat cold, and can also help relieve discomfort caused by damp heat in the body.

[0041] Anti-inflammatory and analgesic: The components contained in the leaves have certain anti-inflammatory effects. When used externally, they can relieve skin inflammation and itching and swelling caused by mosquito bites. When taken internally, they have a certain soothing effect on oral ulcers and swollen gums.

[0042] Promotes digestion: Drinking this infusion can help promote gastrointestinal motility and relieve indigestion, bloating, and other problems. It is suitable for people with weak gastrointestinal function to drink in moderation.

[0043] Diuretic and anti-edema effects: It can promote the metabolism of water in the body, help relieve mild edema, and has certain benefits for the health of the urinary system.

[0044] Example 1

[0045] The preparation of passion fruit leaf tea includes the following four main parts:

[0046] 1. Raw material preparation

[0047] Fresh passion fruit leaves: Select fresh passion fruit buds and leaves, wash them with clean water, and spread them out to dry for 4-6 hours to evaporate some of the surface and shallow layer of moisture until the leaves soften (about 70% water content). Then use a special knife to cut them into strips about one centimeter wide.

[0048] 2. One-time pre-treatment stir-frying

[0049] The processed fresh tea leaves are then subjected to a process called "killing green": First, heat the tea-frying pan to 200-220℃, put in an appropriate amount of fresh tea leaves, and start to continuously squeeze and stir-fry them with your palms.

[0050] Stir-fry for 2-3 minutes until the leaves soften and emit a fragrance. Remove the leaves from the pot, let them cool to room temperature, and then knead them into strips.

[0051] 3. Second stir-frying

[0052] After kneading, put the tea leaves back into the wok (wok temperature 80-100℃), and stir-fry over low heat for 15-20 minutes to completely remove the moisture and dry the leaves.

[0053] During the roasting process, the tea leaves need to be constantly turned and pressed to ensure that they are heated evenly and to retain the moisture between the leaf molecules until the passion fruit aroma is fully released. At this point, the moisture content of the leaves drops to below 5%, and the color is yellowish-green or dark green. The passion fruit tea is then ready.

[0054] 4. Cooling and Storage

[0055] Once the passion fruit tea leaves are roasted, immediately spread them out to cool to room temperature to remove any broken leaf powder that appeared during the roasting process.

[0056] Pack the selected top-grade tea leaves into an airtight container and store them in a cool, dry place, avoiding direct sunlight and odor contamination. The flavor will be even better after letting them sit for 1-2 weeks.

[0057] Example 2

[0058] Based on the four main parts in Example 1, raw material preparation includes fresh leaf picking and acceptance, withering, primary pre-treatment frying includes fixation and rolling, secondary frying includes drying, and cooling and storage includes refining and packaging. More specifically, the passion fruit leaf tea production process includes:

[0059] 1. Fresh leaf picking and acceptance

[0060] Raw materials are the foundation of quality. Passion fruit leaves that are moderately tender, uniformly shaped, and have buds should be picked to ensure that the buds and leaves are intact, fresh, free from pests, and without discoloration.

[0061] After harvesting, the leaves should be transported to the processing site promptly to avoid piling up and generating heat. Strict inspection and grading are required; substandard buds, old leaves, stems, and debris must be removed. After washing, the leaves are cut into 1-centimeter-wide strips.

[0062] 2. Spread out to wither:

[0063] Spread the fresh leaves thinly on a clean, cool, and well-ventilated bamboo mat or a special greening equipment, with a thickness of 2-5 centimeters.

[0064] The spreading time is adjusted according to the moisture content, tenderness of the fresh leaves and the ambient temperature and humidity, and is usually 4-8 hours.

[0065] This step aims to allow the fresh leaves to naturally lose some moisture (approximately 10-15%), transforming the leaves from brittle and hard to soft, making them easier to stir-fry later. At the same time, it promotes the volatilization of low-boiling-point grassy substances and the slight hydrolysis of some macromolecular substances, laying the foundation for the formation of aroma and flavor.

[0066] 3. Fixing (core process, key to determining the quality of passion fruit leaf tea)

[0067] Purpose:

[0068] High temperatures rapidly destroy the activity of oxidases, preventing the enzymatic oxidation of polyphenols and maintaining the clear broth from the green leaves;

[0069] It emits a grassy scent and develops a leafy aroma;

[0070] Evaporating some of the moisture softens the leaves, making them easier to knead and shape.

[0071] Way:

[0072] The main method of blanching is by hand in a wok, which requires a high wok temperature (usually 180-260℃) and an appropriate amount of leaves.

[0073] The key is to achieve high-temperature rapid sterilization to quickly destroy enzyme activity.

[0074] Key points:

[0075] Even and thorough sterilization: The leaves are heated evenly, without scorched edges or spots. The leaf color changes from bright green to dark green and loses its luster. The leaves are soft, can be squeezed into a ball by hand, and the stems do not break when broken. The grassy smell disappears and a fresh fragrance is revealed.

[0076] The process combines steaming and tossing: steaming promotes heat conduction, while tossing helps dissipate water vapor and grassy smell, preventing the food from turning yellow or becoming watery and stale. Strict control of time (generally 2-6 minutes) and water loss rate (approximately 30-40%) is required.

[0077] 4. Kneading (shaping and improving internal quality):

[0078] Tightly roll the tea leaves to shape them (such as strips, needles, etc.);

[0079] By moderately damaging the leaf cell tissue, the tea juice is squeezed out and adheres to the leaf surface, making it easier to dissolve during brewing and forming a rich and mellow flavor.

[0080] Way:

[0081] Hand kneading or shaping.

[0082] Key points:

[0083] Cold kneading: The blanched leaves need to be cooled to below 60℃ before kneading to prevent the leaves from turning yellow and developing a musty taste;

[0084] Kneading principles: Follow the rhythm of "light-heavy-light" and "slow-fast-slow". In the initial stage, apply light pressure and knead slowly to form strips. In the middle stage, increase pressure to accelerate the process, promoting cell breakage and tightening of the strips. In the later stage, apply light pressure and knead slowly to refine the strips and reduce breakage.

[0085] The time is generally 20-60 minutes, which needs to be adjusted according to the grade and appearance requirements of the tea.

[0086] Break up clumps promptly during or after kneading to release heat and moisture, prevent yellowing, and sift to ensure uniformity.

[0087] 5. Drying (shaping, aroma enhancement, and preservation):

[0088] Purpose:

[0089] Further evaporate the moisture to achieve a final moisture content of ≤7%, thus fixing the quality and preventing mold growth;

[0090] Shape the final appearance, develop and fix the aroma (such as fresh, fruity, smoky, etc.), and remove the raw taste.

[0091] Way:

[0092] It is usually divided into two stages: initial drying and final drying, with the leaves needing to be spread out to cool and rehydrate in between.

[0093] 6. Refining and Packaging:

[0094] Cooling: After the tea leaves are fully dried, they need to be cooled to room temperature to prevent residual heat from causing a deterioration in quality;

[0095] Sorting: Manually remove yellow leaves, tea stems, chaff, and impurities to improve purity;

[0096] Grading: Grading is based on appearance (strips, color) and internal quality (aroma, taste);

[0097] Packaging: Use moisture-proof, gas-barrier, and light-proof materials (such as aluminum foil composite bags or tin cans) for sealed packaging. Vacuuming or nitrogen filling is recommended. Store in a low-temperature, dry, light-proof, and odorless environment.

[0098] Based on the above summary, passion fruit leaf tea is characterized by "clear soup and green leaves". Its quality depends on rapid and thorough dehydration and passivation treatment to prevent oxidation (fermentation) and thus retain the natural substances in the fresh leaves, such as chlorophyll, amino acids, unique fruit aroma and other nutrients to the maximum extent.

[0099] The process of frying passion fruit leaf tea is a series of interconnected and meticulously controlled steps, with the control of "temperature, humidity, time, and intensity" being of paramount importance. Even slight differences in each step can significantly affect the color, aroma, taste, and appearance of the finished tea, demonstrating the exquisite and subtle nature of tea-making craftsmanship.

[0100] The examples described herein are merely illustrative, used to explain some features of the methods described herein. The appended claims are intended to claim the broadest possible scope, and the embodiments presented herein are merely illustrative of selected implementations based on combinations of all possible embodiments. Therefore, the applicant intends that the appended claims are not limited by the selection of examples illustrating the features of the invention. Some numerical ranges used in the claims also include sub-ranges within them, and variations within these ranges should be interpreted, where possible, as covered by the appended claims.

Claims

1. A process for making passion fruit leaf tea, characterized in that, Includes the following steps: S1. Fresh leaf picking and acceptance: Pick passion fruit fresh leaves with moderate tenderness and uniform buds, and after sorting and washing, cut them into leaf strips with a width of 0.8-1.2 cm. S2. Spreading and wilting: Spread the leaf strips obtained in step S2 in a cool and ventilated place, with a thickness of 2-5 cm, for 4-8 hours until the water loss rate of the fresh leaves is 10-15%. S3. Blanching: Blanch the withered leaves by hand in a wok at 180-260℃ for 2-6 minutes, using a combination of steaming and tossing, until the leaves turn dark green, the grassy smell disappears, a fresh fragrance appears, and the water loss rate reaches 30-40%. S4. Kneading: After the blanched leaves have cooled to below 60℃, knead them. The kneading process follows the pressure principle of "light-heavy-light" and the speed principle of "slow-fast-slow". The total time is 20-60 minutes, during which the leaves are broken up and sieved. S5. Drying: The rolled leaves are dried in stages to ensure that the moisture content of the tea leaves is ≤7%. S6. Refining and Packaging: After the dried tea leaves are cooled, sorted, and graded, they are sealed in moisture-proof and light-proof materials.

2. The passion fruit leaf tea production process according to claim 1, characterized in that, In step S1, the picking criteria for the fresh leaves are: intact buds and leaves, fresh, free from pests, and free from discolored buds.

3. The process for making passion fruit leaf tea according to claim 1, characterized in that, In step S2, the environmental conditions for spreading and wilting are: temperature 20-28℃, relative humidity 60-75%.

4. The process for making passion fruit leaf tea according to claim 1, characterized in that, In step S3, the amount of leaves added during the blanching process is adapted to the pan temperature. After adding the leaves, the leaf temperature rises to above 80°C within 1 minute to quickly deactivate the oxidase activity.

5. The process for making passion fruit leaf tea according to claim 1, characterized in that, In step S3, the "combination of steaming and tossing" specifically means: first steaming for 20-40 seconds to ensure the leaves are heated evenly, then tossing for 10-20 seconds to release moisture and grassy aroma, and repeating this alternating cycle.

6. The process for making passion fruit leaf tea according to claim 1, characterized in that, In step S4, the specific process of kneading is as follows: initially, light pressure and slow kneading for 5-15 minutes; in the middle stage, heavy pressure and fast kneading for 10-30 minutes; and in the later stage, light pressure and slow kneading again for 5-15 minutes, in order to initially form strips, promote cell breakage, and finally shape the strips.

7. The process for making passion fruit leaf tea according to claim 1, characterized in that, In step S5, the staged drying specifically includes: Preheating stage: temperature 90-110℃, duration 10-20 minutes, followed by cooling and rehydration for 30-60 minutes; The final drying stage: the temperature is 70-90℃, and the duration is 20-40 minutes, until completely dry.

8. The process for making passion fruit leaf tea according to claim 7, characterized in that, In step S6, the sealed packaging is either vacuum packaging or nitrogen-filled packaging.

9. The process for making passion fruit leaf tea according to claim 1, characterized in that, In step S6, the grading is based on the tightness of the tea leaves, the uniformity of color, the purity of the aroma, and the mellowness of the taste.

10. A passion fruit leaf tea prepared by the process described in any one of claims 1-9, characterized in that, The tea soup is clear green, with a delicate aroma and mellow taste, and the tea leaves are intact and emerald green.